Running HandBrake I thought the PC fan was running odd. All four cores were running flat out so I checked the CPU temp with SI. Average was around 97 Celsius. Shut it down in a hurry and sure enough the CPU heat-sink was plugged. Cleaned it up, ran Handbrake again and I got rid of 30 C. Odd thing is that my better half, where the cats roam free, had a cleaner PC than mine;I semi-routinely clean both at the same time.